Injection Molded Resin Article With Local Through-Hole Sealing
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Solution Overview
Problem
Conventional printed wiring board molded products require a cover film that covers the entire surface, which limits their application to 3D-shaped products and can result in bubbles and wrinkles, and they cannot be partially formed on through holes involved in conduction, leading to potential disconnection due to heat and resin pressure during injection.
Innovation Solution
An injection molded article with a base sheet having a conductive layer on one surface and another conductive layer connected via a conductive material through a through hole, where a sealing material covers the through hole and is formed from the same material as the conductive material, preventing disconnection by inhibiting the flow of conductive material under resin pressure, and optionally using a flexible printed wiring board for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cover film is formed on the entire surface of the base sheet to prevent conduction damage during resin injection, then the conductive layers are protected from heat and resin pressure, but the device complexity increases and bubbles and wrinkles may occur in the layer between the cover film and base sheet
Solution Approach 1:
The patent applies local quality by forming the sealing material only at specific locations (through holes and conductive layer regions) rather than covering the entire base sheet surface. This localized sealing approach protects the conductive layers from heat and resin pressure while eliminating the complexity and defects associated with full-surface cover films.
Solution Approach 2:
The patent extracts the sealing function from a general cover film structure and concentrates it into specific sealing material regions positioned only where needed (at through holes and conductive layers). This extraction eliminates unnecessary material and structural complexity while maintaining the essential protection function.
2Reliability
If a cover film is used to protect conductive layers during injection molding, then disconnection between conductive layers is prevented, but it cannot be applied to 3D-shaped molded products and requires additional layers
Solution Approach 1:
The sealing material is applied locally at through holes and conductive layer positions rather than as a comprehensive cover film. This localized approach allows the base sheet to conform to 3D-shaped molded products without the constraints and defects inherent in full-surface cover films, while still providing necessary protection to maintain electrical connection reliability.
3Reliability
If a cover film is formed over the entire base sheet surface, then conductive layers are protected during resin injection, but material waste increases and production efficiency decreases
Solution Approach 1:
The sealing material is applied only at specific locations (through holes and conductive layer regions) rather than covering the entire base sheet surface. This localized sealing reduces material consumption and eliminates the production inefficiencies associated with forming, handling, and adhering large-area cover films, while still providing necessary protection during resin injection.
Solution Approach 2:
The patent extracts the sealing function from a comprehensive cover film and concentrates it into minimal necessary regions. This extraction eliminates unnecessary material usage and the associated production inefficiencies, while maintaining effective protection of conductive layers during the resin injection process.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents disconnection between conductive layers and reduces material usage by eliminating the need for a terminal, allowing for reliable electrical connection and simplified configuration, especially in touch panels and 3D-shaped products.
Implementation Method 1
the injection molded resin makes it difficult for the conductive material in the through hole to flow
Implementation Method 2
the sealing material is composed of the same material as the conductive material
Data Source
AI summary
An injection molded article is provided with: a flat molded resin body that has a flat rectangular parallelepiped shape and is formed from an injection molded resin; and a base sheet affixed to the surface of the molded resin body. The base sheet has formed therein a first conductive layer on a first surface and a through hole passing through from the first surface to a second surface. The through hole is filled with a conductive material, and a second conductive layer is formed so as to be electrically connected with the first conductive layer via the conductive material with which the through hole is filled. In addition, a sealing material is formed on the first conductive layer so as to cover the through hole. The molded resin body is fixed together with the first surface side of the base sheet so as to cover the sealing material.